1. Field
The invention is in the field of securing working tips to tools such as power drills or screwdrivers so that the tool with working tip secured may be manipulated or rotated to perform a desired task, and the tip may be easily and quickly changed so that the tool can perform other tasks.
2. State of the Art
Various tools provide interchangeable working tips. Power tools such as power drills generally include chucks which allow tips, such as drills, of a wide range of sizes to be secured in working position in the drill. However, chucks are relatively large, heavy, and expensive compared to the rest of the drill and because of the size and weight of the chucks, power drills and other tools using chucks are often designed around the chuck to maintain proper balance and feel of the drill or other tool. Further, chucks can be difficult to use and tighten properly to securely and safely hold a bit or other tip in place in the chuck. Bits often become loose in a chuck during use and sometimes even separate from a chuck during use.
U.S. Pat. No. 4,572,038 shows a tool having a plurality of working tips, such as screwdriver tips or drills, housed in compartments in a cylinder which is rotated to align the desired tip with the tool shaft. The tool shaft is retracted from the cylinder during selection of a tip to allow rotation of the cylinder to align the desired tip with the tool shaft. As a tip comes into alignment with the tool shaft during rotation of the cylinder, it engages the tool shaft. When the desired tip is aligned, and therefore engaged with the shaft, the shaft is extended through the cylinder so that the end of the working tip extends from the end of the tool. The engaged ends of the tip and shaft are maintained in a sleeve which holds the engagement during use of the tool and under various torque and other loads.
The tool of U.S. Pat. No. 4,572,038 may be used as a hand tool, as an attachment to a power tool such as a power drill or screwdriver, or incorporated into a power tool. The advantage of such a tool is that it is fast and easy to change tips between the limited number of preselected available tips by merely retracting the shaft, turning the cylinder to align the desired tip, and then again extending the shaft. This is much easier and faster than opening a chuck, removing a tip, inserting a new tip, and retightening the chuck. The problem with the tool of the cited patent is that the cylinder can be made to accommodate only a limited number of preselected tips. The number of preselected tips available in a particular tool is limited by the practical size of the cylinder to generally between about six to twelve preselected tips. Use of such a tool is limited by the particular preselected tips which come with the tool. A user cannot generally select particular tips to be available in a tool and cannot change the preselected selection of tips in such a tool, or replace a worn or damaged tip, without completely disassembling the tool. This is normally difficult and time-consuming. Because such tools are not designed for a user to change the selection of preselected tips, tips are not available separately for use with such tools.